Hitherto, various products and packs have been developed to provide institutional washing machines, especially dishwashing machines, with a supply of detergent material from which measured amounts of detergent product are dispensed to the wash liquor in the washing machine. These products include detergent products in powder form, in liquid form and in paste form, which are generally packed in supply packs or containers. More recently, solid detergent blocks for institutional washing machines have been developed, which have the advantage of being discretely shaped. Furthermore, solid detergent blocks can contain more concentrated product than the other above-mentioned product types. These block form detergent products are generally dissolved by simply spraying with water in a dispensing device, and then are delivered to the wash liquor. Since detergent products which are suitable for use in institutional washing machines, often have a high alkali content, contact with the skin should be avoided. Block form detergent products appear to be very suitable for avoiding skin contact.
U.S. Pat. No. 4,569,781 (Ecolab) describes a detergent container for a cast detergent solid suitable for use in dishwashing machines. The container contains a detergent product produced from a melt and allowed to solidify. The detergent product is subsequently dissolved from the container on contact with a stream of aqueous liquid from a spray means when placed in a dispensing device. The advantage of a block form detergent product and dispensing device of this type is that, with proper handling, contact with the skin is virtually eliminated. Owing to the shape thereof, however, the container described in this patent has shown to leave residues of detergent after emptying by spraying. This situation is unacceptable for economic, safety and environmental reasons. Detergent residues in the container are a potential danger source to the user when a supposedly empty container is being replaced by a completely full container. Moreover, from an environmental point of view such a rigid container is less attractive because of its impact to the environment and non-collapsibility.
U.S. Pat. No. 4,426,362 (Ecolab) describes a dishwasher distributor for a solid block form moulded detergent product. The block form detergent product of this reference is positioned with its casting mould in the receiving means of the distributor so that the casting mould surrounds the detergent block during the flushing out process and touches it on all sides except for one free face. Once again, contactless handling of the detergent product is provided, but once again, complete emptying is not guaranteed.
U.S. Pat. No. 4,774,014 (Henkel) discloses a detergent supply pack for a cast detergent block which pack is suitable for ready dissolution of the block in the dispensing device associated with an institutional dishwashing machine, such that water consumption is not appreciably higher than in the case of powder-form detergents, even towards the end of the block. However, the detergent supply pack has to be opened before positioning the pack in the dispensing device and therefore skin contact with the alkaline detergent is possible.
It is an object of the present invention to provide a detergent dispensing system comprising a detergent supply pack for a detergent powder or, preferably, a block form detergent product and a dispensing device associated with an institutional washing machine, preferably a dishwashing machine, whereby the supply pack ensures an economic and effective use of the detergent in the dispensing device. It is an other object of the invention to provide a detergent dispensing system whereby the detergent supply pack is adapted to the dispensing device such that the detergent can be introduced into the device without the need to open the pack before positioning the pack in the dispensing device and loading the device. This eliminates the risk of any skin contact and thus contributes to safety. It is a further object of the invention that no residue is left inside the supply pack after emptying and that a minimal amount of packaging material is to be disposed of after introducing the detergent product into the dispensing device.
In European patent application 533,238, a dispensing system comprising a dispensing device and a supply pack for supplying solid state, preferably block, detergent material to the dispensing device is described.
In this system, the supply pack comprises packaging material for solid state detergent material, said solid state detergent material and a closing/release device for promoting release of the solid detergent from the supply pack into the dispensing device, whereby the closing/release device essentially consists of two parts in between which the packaging material is fixed and is adapted to the dispensing device such that the closing/release device can be easily removed in conjunction with the dispensing device for introducing the detergent solid into the dispensing device.
Preferably, the supply pack contains a compacted solid detergent block and comprises packaging material which conforms to the shape of the block.
The above-described dispensing system has the advantage that it is fairly easy to construct and ensures effective use of the solid detergent material. However, we also found that it requires a considerable number of handling steps and that consequently a realistic risk of mal-operation exists resulting in unsafe conditions. It is, therefore, an additional object of the present invention to provide a detergent dispensing system which is user-friendly and requires a limited number of handling steps.
It was found that these and other objects can be accomplished by a detergent dispensing system according to the present invention.